How can you close a channel in the program?

In Go, the close() function is used to finish working with a channel. Closing a channel signals to receivers that no more values will be sent. After closing a channel, attempting to send to it will cause a panic, but reading from a closed channel is possible — it will return the zero value and false as the second return value.

Example:

ch := make(chan int)
go func() {
    ch <- 42
    close(ch) // Close the channel after sending
}()

for val := range ch {
    fmt.Println(val) // Will print 42
}

Thus, to finish working with a channel, you need to call close(channel).